There are several different types of devices that are used to launch a spear underwater. Generally, they are broken into three groups: spearguns, pole spears, and Hawaiian slings. Within these groups, designs vary. In general terms, however, a speargun is a device in which a spear, typically with a barbed tip, is loaded into a barrel. The spear is held in the barrel by a catch that is coupled to a trigger. An elastic rubber tube or band can be stretched and attached to the spear, or a pneumatic chamber can be loaded. Upon depressing the trigger, energy from either such driver is released to launch the spear from the gun. A line and reel are also typically attached to the spear, to recover the spear after a launch.
By contrast, a pole spear more simply includes a shaft with a sharpened tip on one end and a rubber sling on the other. With one hand, a user grips the spear shaft as well as the rubber sling. With his or her second hand, the user pulls back the sling-end of the pole spear, creating tension in the sling. When the user's second hand releases the spear, the spear is propelled forward as the tension in the sling is released, until the sling itself, still held by the first hand, stops the progress of the pole spear.
A Hawaiian sling provides a tubular handle with a hole in the middle, through which the shaft of a spear is received. The elastic band is attached to the tubular handle, and is engaged with the end of the spear, opposite to the point end thereof. A user then holds the handle with one hand, and pulls back the spear and band with the other, and then releases, propelling the spear out of the handle. Like the spear gun, the Hawaiian sling is typically not attached to the elastic member after it is propelled therefrom.
Each of these devices has been used for spearfishing a variety of different types of game fish. In recent years, they have also been used to hunt lionfish (certain species of the genus Pterois), which are invasive and damaging to the environment of the Western Atlantic (e.g., eastern U.S., Caribbean, and South America). The lionfish has few or no natural predators in these environments, but is a successful predator itself. Further, the lionfish have venomous fin rays, which are capable of delivering a potent sting.
Potentially as a consequence of a lack of predators, the lionfish tend to remain stationary, even in the presence of human SCUBA divers. This makes them relatively easy targets for eradication efforts. However, spearguns, as well their spears, are expensive and may be too powerful for such close-up shots, leading to over-penetration and damage to the spears and/or coral or other objects behind the lionfish. Hawaiian slings and pole spears may avoid this drawback, but each generally require an exposed shaft point, which can be dangerous to the spear-fisherman and/or to other divers, and may be inconvenient, especially if use of the pole spear or Hawaiian sling is not the primary purpose of the dive. Further, these devices, while allowing for a relatively low-velocity, close-up shot, may expose the diver to a risk of being stung by the lionfish, either while supporting the spear/handle and drawing back the spear, or when collecting and removing the lionfish from the spear after a successful shot.
What is needed then is a safe and effective device for relatively close range shots, e.g., for spearing lionfish, that protects users from inadvertently puncturing themselves or others with the point of the spear, and from stings by the lionfish (or any other quarry taken by the device).